netfilter: nf_log: consolidate check for NULL logger in lookup function

Consolidate pointer fetch to logger and check for NULL in
__find_logger().

Signed-off-by: Pablo Neira Ayuso <[e-mail]>
Signed-off-by: Florian Westphal <[e-mail]>

net/netfilter/nf_log.c

···
 	int i;
 
 	for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
-		if (loggers[pf][i] == NULL)
+		log = nft_log_dereference(loggers[pf][i]);
+		if (!log)
 			continue;
 
-		log = nft_log_dereference(loggers[pf][i]);
 		if (!strncasecmp(str_logger, log->name, strlen(log->name)))
 			return log;
 	}